BACKGROUND:Laser interstitial thermal therapy (LITT) for glioblastoma (GBM) has been reserved for poor surgical candidates and deep “inoperable” lesions. We present the first reported series of LITT for surgically accessible recurrent GBM (rGBM) that would otherwise be treated with surgical resection.OBJECTIVE:To evaluate the use of LITT for unifocal, lobar, first-time rGBM compared with a similar surgical cohort.METHODS:A retrospective institutional database was used to identify patients with unifocal, lobar, first-time rGBM who underwent LITT or resection between 2013 and 2020. Clinical and volumetric lesional characteristics were compared between cohorts. Subgroup analysis of patients with lesions ≤20 cm3 was also completed. Primary outcomes were overall survival and progression-free survival.RESULTS:Of the 744 patients with rGBM treated from 2013 to 2020, a LITT cohort of 17 patients were compared with 23 similar surgical patients. There were no differences in baseline characteristics, although lesions were larger in the surgical cohort (7.54 vs 4.37 cm3, P = .017). Despite differences in lesion size, both cohorts had similar extents of ablation/resection (90.7% vs 95.1%, P = .739). Overall survival (14.1 vs 13.8 months, P = .578) and progression-free survival (3.7 vs 3.3 months, P = 0. 495) were similar. LITT patients had significantly shorter hospital stays (2.2 vs 3.0 days, P = .004). Subgroup analysis of patients with lesions ≤20 cm3 showed similar outcomes, with LITT allowing for significantly shorter hospital stays.CONCLUSION:We found no difference in survival outcomes or morbidity between LITT and repeat surgery for surgically accessible rGBM while LITT resulted in shorter hospital stays and more efficient postoperative care.

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Laser interstitial thermal therapy (LITT) is a minimally invasive, image-guided, cytoreductive procedure to treat recurrent glioblastoma. This study implemented dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) methods and employed a model selection paradigm to localize and quantify post-LITT blood-brain barrier (BBB) permeability in the ablation vicinity. Serum levels of neuron-specific enolase (NSE), a peripheral marker of increased BBB permeability, were measured. MethodsSeventeen patients were enrolled in the study. Using an enzyme-linked immunosorbent assay, serum NSE was measured preoperatively, 24 hours postoperatively, and at two, eight, 12, and 16 weeks postoperatively, depending on postoperative adjuvant treatment. Of the 17 patients, four had longitudinal DCE-MRI data available, from which blood-to-brain forward volumetric transfer constant (K trans ) data were assessed. Imaging was performed preoperatively, 24 hours postoperatively, and between two and eight weeks postoperatively. ResultsSerum NSE increased at 24 hours following ablation (p=0.04), peaked at two weeks, and returned to baseline by eight weeks postoperatively. K trans was found to be elevated in the peri-ablation periphery 24 hours after the procedure. This increase persisted for two weeks. ConclusionFollowing the LITT procedure, serum NSE levels and peri-ablation K trans estimated from DCE-MRI demonstrated increases during the first two weeks after ablation, suggesting transiently increased BBB permeability.

INTRODUCTION Laser Interstitial thermal therapy (LITT) is a minimal-access procedure for intracranial tumors that are either refractory to standard treatment paradigms or difficult to access via conventional open surgery. OBJECTIVE To evaluate predictors of local disease control following LITT in patients with primary and secondary brain tumors. METHODS Single-center retrospective cohort study of all consecutive LITT ablations between 2014 and 2019. Demographic and procedural characteristics analyzed with respect to local disease control at 6 months. Chi-square tests for categorical variables, T-tests/Wilcoxon Rank-Sum tests for continuous variables for parametric and non-parametric data, respectively. Poisson regression models were used to approximate relative risk (RR) with 95% confidence intervals. RESULTS A total of 76 patients underwent LITT with a median follow up of 12.3 months; pathology at time of ablation was glioblastoma multiforme (GBM, 36%), WHO grade III primary CNS (24%), low grade CNS (20%), and metastatic lesions (19%) with respective local control rates of 26%, 20%, 29%, and 26%. Pathology of GBM (RR 0.46, 0.21-1.02, p=0.055) and a 5-year increase in age at the time of ablation (RR 0.91, 0.83-0.99, p=0.028) were associated with a lower likelihood of local control at 6 months. Preoperative Karnofsky performance status (KPS) of 100 (RR 2.04, 1.13-3.69, p=0.019) was associated with a higher likelihood of local control. Extent of ablation (EOA) demonstrated a direct relationship with local control; when EOA=100% local control was 59%, with this rate dropping down to 21% when EOA=90%. Tumor location, lesion volume, gender, BMI, ethnicity, or whether there existed multiple foci of disease at the time of ablation had no strong association with local control. CONCLUSION Our series demonstrates that preoperative performance status and age were strong predictors of local disease control following LITT. Incomplete ablation and histology of high-grade glioma portended a higher risk of local recurrence.